1. Field of the Invention
The invention relates to a power capacitor comprising a plurality of round, wound elements accommodated in a common housing.
2. Description of the Prior Art
The previously customary power capacitors of this kind have, as a rule, a housing of round, circular cross-section or rectangular cross-section. Power capacitors with circular, round housings have, among other things, the disadvantage that any arrangement in which a plurality of such capacitors are arranged alongside one another requires a relatively large amount of space. Moreover, the outer cooling surface of such capacitors is relatively small. Capacitors with housings with a rectangular or square cross-section can admittedly be better placed together in a row. However, it is a disadvantage of such capacitors that when using round coils, the housing volume is only poorly exploited. In the known capacitors it is frequently also necessary for electrical connections of different potential to cross one another, which is, as a rule, associated with a relatively high insulating cost and complexity for the associated wiring. Moreover, the construction of electrical delta circuits always leads, both with round coils arranged above one another alongside one another and also with concentric round coils, to dissimilar, asymmetric line lengths with crossing lines of high potential difference, which, among other things, gives rise to the disadvantage of non-symmetrical series resistances and inductivities, and also to the danger of insulation faults. In connection with star circuits With round windings accommodated above one another in cylindrical housings, a relatively high level of cost and complexity for insulation for the lines is generally necessary and much space is required in order to form the star point and to lead the phase lines upwardly to the common connection.
Moreover, with fully potted, round, wound embodiments in the cylindrical housing, the possibility of leading off the gas which arises into the connection space, without a dangerous excess pressure arising, hardly exists in the case of a fault, i.e. in particular, with a non-self healing breakdown with gas formation. Cylindrical, potted capacitors thus require special passages or permeable winding sleeves in order to facilitate the leading off of gas. These additionally required measures are, however, always associated with an increased space requirement, a higher thermal resistance and higher additional costs.